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901
FXUS61 KLWX 290800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Sun Jun 29 2025

.SYNOPSIS...
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A decaying cold front will drop southward into the area today. A
stronger cold front will move through the area on Tuesday. High
pressure will build in for the middle to end of the week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Skies are mostly clear this morning, with just some scattered
high clouds passing through aloft. Patchy fog has started to
form in spots, but overall coverage isn`t high. Any fog will
quickly burn off after sunrise.

A decaying cold front (really more a wind shift) will drop
southward into area today. Temperatures will remain similar to
yesterday behind the front, but some subtle drying may occur at
low-levels across northern Maryland by afternoon. The majority
of the area will remain in a very humid, moisture-laden airmass
however, with precipitable water values near 2 inches. Showers
and thunderstorms will form within the warm and humid airmass
this afternoon in response to daytime heating. CAMs suggest that
initial development of storms will likely occur during the early
to mid afternoon hours in the Shenandoah Valley, and also along
bay/river breezes further east. While instability will be
plentiful (around 2000 J/kg MLCAPE), steering flow will be weak
(around 10-15 knots of westerly flow in the mid-levels). As a
result, storm motions will be somewhat chaotic, and largely
driven by outflow boundaries today. Outflows from storms to the
west of the Blue Ridge may eventually meet up with outflows from
bay/river breeze storms by later this afternoon into this
evening. With the somewhat chaotic storm motions, it`s difficult
to time the storms in any one given location, with a general
risk for thunderstorms throughout much of the area during the
afternoon and evening hours.

In terms of hazards, storms today will be capable of producing
localized wet microbursts and heavy rainfall. The lack of an
obvious surface feature to focus convergence should limit the
potential for flash flooding, although an isolated instance or
two can`t be ruled out. Both SPC and WPC have much of the area
outlooked in Marginal Risks today.

Storms should gradually wind down through the late evening/early
overnight hours, with dry conditions expected during the second
half of the night. Some patchy fog also try to form prior to
daybreak. Low temperatures will generally be in the upper 60s
and lower 70s.
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&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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A very similar warm and humid airmass will remain in place
across the area tomorrow. Temperatures will once again climb
into the upper 80s to around 90, with showers and thunderstorms
forming in response to daytime heating during the afternoon
hours. Model soundings show slightly greater instability (closer
to 3000 than 2000 J/kg of MLCAPE), and slightly stronger mid-
level flow (around 15-20 knots), with continued deep near-saturation
and modest DCAPE values (500-800 J/kg). As a result, storms may
show slightly more organization, especially across northwestern
portions of the forecast area, where they`ll be closer to an
approaching upper trough moving in from the Great Lakes. Both
SPC and WPC once again have the bulk of the area outlooked in
Marginal Risks.

The aforementioned upper trough will progress further east on
Tuesday as a seasonably strong area of low pressure tracks
across Quebec. A trailing cold front will approach the area from
the northwest during the day Tuesday, before eventually moving
through Tuesday night. Showers and thunderstorm are expected to
form along a pre-frontal trough Tuesday afternoon and move
through the area from west to east. With flow aloft increasing
as the upper trough approaches, storms on Tuesday should be
better organized, and could potentially pose a greater threat
for damaging winds compared to today and tomorrow. Isolated
instances of flash flooding can`t be ruled out as well.
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&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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An upper-level trough will remain in place for Wednesday and
Thursday with surface high pressure nearby. A west to northwest flow
at the low and mid-levels will allow for dry conditions for this
time of year. Therefore, the probability for convection will be low
along with seasonable temperatures and relatively lower humidity.

The upper-level trough will most likely depart while the subtropical
ridge builds closer to the area for Friday through Sunday. With the
ridge building overhead, this will keep the probability for
convection to be low with plenty of sunshine each day. A warming
trend in temperatures is expected due to the stronger subsidence,
especially for Saturday and Sunday with temperatures most likely in
the 90s. For the Fourth of July, the most likely scenario is for a
seasonably warm day with sunshine and a low chance for convection.
However, this will continue to be monitored since it is several days
out.
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&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
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Patchy fog is starting to develop across the area early this
morning, and could potentially impact some of the terminals
briefly prior to sunrise. Any fog will quickly burn off after
sunrise, with prevailing VFR conditions expected through the
day. Showers and thunderstorms will be possible on and off
through the afternoon and evening. In the absence of any well-
defined surface features, storm movement will mainly be driven
by outflows, and as a result timing the storm at any given
terminal is difficult at this point. Have maintained longer
PROB30 groups with -TSRA at most of the terminals until
confidence in timing increases further. Showers and
thunderstorms should wind down prior to midnight, with quiet
conditions expected overnight. Some patchy fog may be possible
again tonight, especially in areas that receive rain during the
daylight hours.

Prevailing VFR conditions will continue through Monday and
Tuesday, with chances for showers and thunderstorms each
afternoon and evening. Areal coverage of storms should be
greatest on Tuesday as a cold front approaches from the north
and west. Winds will be light out of the northwest today, before
turning out of the south tomorrow, and then southwest on
Tuesday.

VFR conditions are most likely for Wednesday and Thursday with high
pressure nearby.
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&&

.MARINE...
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Light and variable winds are expected over the waters today.
Winds will become southerly tomorrow, and then southwesterly on
Tuesday. Winds may reach low-end SCA levels Monday into the day
Tuesday. SMWs associated with showers and thunderstorms may be
possible each afternoon and evening through Tuesday.

High pressure will remain near the waters for Wednesday and
Thursday. Winds are most likely to be below SCA criteria.
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&&

.TIDES/COASTAL FLOODING...
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Several sites will reach Action stage with the tidal cycle this
morning. Thereafter, anomalies are expected to drop, with no
tidal flooding concerns over the next couple days.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...KJP
NEAR TERM...KJP
SHORT TERM...KJP
LONG TERM...BJL
AVIATION...BJL/KJP
MARINE...BJL/KJP
TIDES/COASTAL FLOODING...KJP